1 Alzheimer's disease (AD), the most common cause of dementia, disproportionately affects adults over age 2 65. Its prevalence is expected to grow significantly?particularly as the US population ages. These aging 3 AD patients will increasingly be affected by diseases of aging, such as cataracts (progressive clouding of 4 the natural crystalline lens in the eye), which cause visual impairment, with associated reduction in quality of 5 life and physical function. Poor vision is also associated with cognitive decline and poor cognitive function 6 among patients with dementia. Fortunately, cataracts are reversible, able to be treated with what is usually 7 a short outpatient surgery under sedation and topical or local anesthesia. However, surgery can be complex 8 and complications can occur?particularly among patients who may become disoriented or are unable to lie 9 still and cooperate with surgery (as may be the case in AD). And, among patients who are less active, the 10 benefits of surgery are less clear, particularly if coming in for care is a hardship (due to advanced dementia, 11 frailty, and/or limited caregiver support). To date, there is a lack of evidence-based guidelines to guide 12 surgical decision-making?an unmet need for research. 13 14 We hypothesize that patients with Alzheimer's disease will be less likely to see an ophthalmologist and to 15 undergo cataract surgery, and more likely to require additional resources and/or have surgical complications 16 when they do undergo surgery. However, surgery may still have beneficial effects in AD patients, reflected in 17 reduced rates of measurable events such as fractures, mortality, and healthcare utilization. To test these 18 hypotheses, we will use Medicare claims data to evaluate rates of cataract surgery, surgical complexity, and 19 need for ancillary resources among AD patients, compared to a similar population of patients without 20 dementia, and we will begin to investigate the impact of cataract surgery on general health and function 21 among AD patients?rates of surgical complications, mortality, fractures, and hospitalizations or emergency 22 department visits. This will be the first study to specifically explore current practice, value, and practical 23 considerations of cataract surgery in patients with AD, at a scale only feasible with large data sets such as 24 Medicare claims. This research is clinically significant because it will investigate fundamental differences in 25 cataract surgery for AD patients, laying a foundation for subsequent studies that will incorporate clinical data 26 on Alzheimer's disease severity and trajectory, to assess the value and impact of cataract surgery on quality 27 of life and (physical and cognitive) function. Our ultimate objective will be to provide robust data on health and 28 quality of life outcomes, supporting the development of clinical guidelines for targeted therapy.